Non-Monotonic Spatial Reasoning with Answer Set Programming Modulo Theories
This addresses the need for systematic modelling in dynamic spatial systems for applications like robotics and GIS, but it appears incremental as it builds on existing ASPMT and SMT methods.
The paper tackles the problem of non-monotonic spatial reasoning in dynamic systems by developing ASPMT(QS), a novel approach that integrates qualitative spatial representation with Answer Set Programming Modulo Theories, and it demonstrates capabilities in reasoning about indirect spatial effects and integrating geometric information, though no concrete performance numbers are provided in the abstract.
The systematic modelling of dynamic spatial systems is a key requirement in a wide range of application areas such as commonsense cognitive robotics, computer-aided architecture design, and dynamic geographic information systems. We present ASPMT(QS), a novel approach and fully-implemented prototype for non-monotonic spatial reasoning -a crucial requirement within dynamic spatial systems- based on Answer Set Programming Modulo Theories (ASPMT). ASPMT(QS) consists of a (qualitative) spatial representation module (QS) and a method for turning tight ASPMT instances into Satisfiability Modulo Theories (SMT) instances in order to compute stable models by means of SMT solvers. We formalise and implement concepts of default spatial reasoning and spatial frame axioms. Spatial reasoning is performed by encoding spatial relations as systems of polynomial constraints, and solving via SMT with the theory of real nonlinear arithmetic. We empirically evaluate ASPMT(QS) in comparison with other contemporary spatial reasoning systems both within and outside the context of logic programming. ASPMT(QS) is currently the only existing system that is capable of reasoning about indirect spatial effects (i.e., addressing the ramification problem), and integrating geometric and qualitative spatial information within a non-monotonic spatial reasoning context. This paper is under consideration for publication in TPLP.